Add npm script to check TypeScript

"npm run lint" will compile the TypeScript code to check types.

Author: wimpyprogrammer

package.json

@@ -11,6 +11,7 @@
   "scripts": {
     "build": "npm run clean && babel src -d lib --extensions '.js,.ts'",
     "clean": "rimraf lib/*",
+    "lint": "tsc",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "dependencies": {},
@@ -19,6 +20,7 @@
     "@babel/core": "^7.0.0-beta.54",
     "@babel/preset-env": "^7.0.0-beta.54",
     "@babel/preset-typescript": "^7.0.0-beta.54",
-    "rimraf": "^2.6.2"
+    "rimraf": "^2.6.2",
+    "typescript": "^2.9.2"
   }
 }

tsconfig.json

@@ -0,0 +1,18 @@
+{
+	"compilerOptions": {
+		"allowJs": true,
+		"allowSyntheticDefaultImports": true,
+		"baseUrl": "./",
+		"rootDir": "./",
+		"module": "es2015",
+		"noEmit": true,
+		"noUnusedLocals": true,
+		"noUnusedParameters": true,
+		"pretty": true,
+		"skipLibCheck": true,
+		"sourceMap": true
+	},
+	"include": [
+		"src"
+	]
+}

yarn.lock

@@ -1727,6 +1727,10 @@ trim-right@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/trim-right/-/trim-right-1.0.1.tgz#cb2e1203067e0c8de1f614094b9fe45704ea6003"
 
+typescript@^2.9.2:
+  version "2.9.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.9.2.tgz#1cbf61d05d6b96269244eb6a3bce4bd914e0f00c"
+
 unicode-canonical-property-names-ecmascript@^1.0.4:
   version "1.0.4"
   resolved "https://registry.yarnpkg.com/unicode-canonical-property-names-ecmascript/-/unicode-canonical-property-names-ecmascript-1.0.4.tgz#2619800c4c825800efdd8343af7dd9933cbe2818"